OpenSceneGraph/include/osgDB/Registry

//C++ header - Open Scene Graph - Copyright (C) 1998-2001 Robert Osfield
//Distributed under the terms of the GNU Library General Public License (LGPL)
//as published by the Free Software Foundation.

#ifndef OSGDB_REGISTRY
#define OSGDB_REGISTRY 1

#include <vector>
#include <map>
#include <string>

#include <osg/ref_ptr>

#include <osgDB/DynamicLibrary>
#include <osgDB/ReaderWriter>
#include <osgDB/DotOsgWrapper>

namespace osgDB {

/**
    Registry is a singleton factory which stores
    the reader/writers which are linked in
    at runtime for reading non-native file formats.

    The RegisterDotOsgWrapperProxy can be used to automatically register
    DotOsgWrappers, at runtime with the Registry. A DotOsgWrapper encapsulates
    the functions that can read and write to the .osg for each osg::Object.

    The RegisterReaderWriterProxy can be used to automatically
    register at runtime a reader/writer with the Registry.
*/
class OSGDB_EXPORT Registry
{
    public:

        ~Registry();

        static Registry* instance();


        /** register an .fileextension alias to mapExt toExt, the later
	  * should the the extension name of the readerwriter plugin library.
	  * For example to map .tif files to the tiff loader, use
	  * addExtAlias("tif","tiff") which will enable .tif to be read
	  * by the libdb_tiff readerwriter plugin.*/
	void addFileExtensionAlias(const std::string mapExt, const std::string toExt);

        void addDotOsgWrapper(DotOsgWrapper* wrapper);
        void removeDotOsgWrapper(DotOsgWrapper* wrapper);

        void addReaderWriter(ReaderWriter* rw);
        void removeReaderWriter(ReaderWriter* rw);

        /** create the platform specific library name associated with file.*/
        std::string createLibraryNameForFile(const std::string& fileName);

        /** create the platform specific library name associated with file extension.*/
        std::string createLibraryNameForExt(const std::string& ext);

        /** find the library in the SG_LIBRARY_PATH and load it.*/
        bool loadLibrary(const std::string& fileName);
        /** close the attached library with specified name.*/
        bool closeLibrary(const std::string& fileName);

        osg::Object*         readObjectOfType(const osg::Object& compObj,Input& fr);

        osg::Object*         readObject(Input& fr);
        osg::Image*          readImage(Input& fr);
        osg::Drawable*       readDrawable(Input& fr);
        osg::StateAttribute* readStateAttribute(Input& fr);
        osg::Node*           readNode(Input& fr);
        
        bool                 writeObject(const osg::Object& obj,Output& fw);

        
        ReaderWriter::ReadResult readObject(const std::string& fileName);
        ReaderWriter::WriteResult writeObject(const osg::Object& obj, const std::string& fileName);

        ReaderWriter::ReadResult readImage(const std::string& fileName);
        ReaderWriter::WriteResult writeImage(const osg::Image& obj, const std::string& fileName);

        ReaderWriter::ReadResult readNode(const std::string& fileName);
        ReaderWriter::WriteResult writeNode(const osg::Node& node, const std::string& fileName);
        
        void setCreateNodeFromImage(bool flag) { _createNodeFromImage = flag; }
        bool getCreateNodeFromImage() const { return _createNodeFromImage; }

        void setOptions(ReaderWriter::Options* opt) { _options = opt; }
        ReaderWriter::Options* getOptions() { return _options.get(); }
        const ReaderWriter::Options*  getOptions() const { return _options.get(); }


    private:

        typedef std::map<std::string,osg::ref_ptr<DotOsgWrapper> >  DotOsgWrapperMap;
        typedef std::vector<osg::ref_ptr<ReaderWriter> >            ReaderWriterList;
        typedef std::vector<osg::ref_ptr<DynamicLibrary> >          DynamicLibraryList;
        typedef std::map<std::string,std::string>                   ExtensionAliasMap;

        /** constructor is private, as its a singleton, preventing
            construction other than via the instance() method and
            therefore ensuring only one copy is ever constructed*/
        Registry();
        
        /** get the attached library with specified name.*/
        DynamicLibraryList::iterator getLibraryItr(const std::string& fileName);
        DynamicLibrary*              getLibrary(const std::string& fileName);

        bool _createNodeFromImage;

        osg::Object*       readObject(DotOsgWrapperMap& dowMap,Input& fr);

        DotOsgWrapperMap   _objectWrapperMap;
        DotOsgWrapperMap   _imageWrapperMap;
        DotOsgWrapperMap   _drawableWrapperMap;
        DotOsgWrapperMap   _stateAttrWrapperMap;
        DotOsgWrapperMap   _nodeWrapperMap;
        
        DotOsgWrapperMap   _classNameWrapperMap;

        ReaderWriterList    _rwList;
        DynamicLibraryList  _dlList;

        bool _openingLibrary;
	
	// map to alias to extensions to plugins.
	ExtensionAliasMap  _extAliasMap;
        
        // options to pass to reader writers.
        osg::ref_ptr<ReaderWriter::Options>  _options;

};

/**  Proxy class for automatic registration of DotOsgWrappers with the Registry.*/
class RegisterDotOsgWrapperProxy
{
    public:
    
        RegisterDotOsgWrapperProxy(osg::Object* proto,
                                   const std::string& name,
                                   const std::string& associates,
                                   DotOsgWrapper::ReadFunc readFunc,
                                   DotOsgWrapper::WriteFunc writeFunc,
                                   DotOsgWrapper::ReadWriteMode readWriteMode=DotOsgWrapper::READ_AND_WRITE)
        {
            if (Registry::instance())
            {
                _wrapper = new DotOsgWrapper(proto,name,associates,readFunc,writeFunc,readWriteMode);
                Registry::instance()->addDotOsgWrapper(_wrapper.get());
            }
        }
        
        ~RegisterDotOsgWrapperProxy()
        {
            if (Registry::instance())
            {
                Registry::instance()->removeDotOsgWrapper(_wrapper.get());
            }
        }
        
    protected:
        osg::ref_ptr<DotOsgWrapper> _wrapper;
};

/** Proxy class for automatic registration of reader/writers with the Registry.*/
template<class T>
class RegisterReaderWriterProxy
{
    public:
        RegisterReaderWriterProxy()
        {
            if (Registry::instance())
            {
                _rw = new T;
                Registry::instance()->addReaderWriter(_rw.get());
            }
        }

        ~RegisterReaderWriterProxy()
        {
            if (Registry::instance())
            {
                Registry::instance()->removeReaderWriter(_rw.get());
            }
        }
        
    protected:
        osg::ref_ptr<T> _rw;
};

};

#endif